1. Field of the Invention
The present invention relates to a display device and a method of driving the same, and more particularly, to a display device including a plurality of pixel electrodes, each partitioned into a main pixel electrode and a subpixel electrode in order to represent different grayscales.
2. Description of the Related Art
A liquid crystal display (LCD) includes a LCD panel which includes a thin-film transistor (TFT) substrate (“lower substrate” below) having a plurality of thin-film transistors formed thereon and an upper substrate which may include a color filter substrate having a color filter layer formed thereon. An LCD panel also includes a liquid crystal layer interposed between the thin-film transistor substrate and the upper substrate. Since the LCD panel is non-self-luminous, a backlight unit may be provided on a rear surface of the LCD panel to emit light.
Generally, LCD panels have a narrower viewing angle (defined as the maximum angle with a contrast ratio of 1:10) than self-luminous display panels. One class of LCD panels is vertical alignment (VA) mode LCD panels. A VA mode LCD panel includes electrodes on the TFT substrate and on the upper substrate. In order to improve the viewing angle in VA mode LCD panels, variations of these panels have been developed, including patterned VA mode LCD panels (having openings formed in electrodes on the upper and lower substrates), multi-domain VA mode LCD panels (having protrusions formed on electrodes on the upper and lower substrates), and mixed VA mode LCD panels (having openings in electrodes on the lower substrate and protrusions on electrodes on the upper substrate).
However, in these LCD panel variations, an image color may depend on the angle at which the image is viewed by an observer. Such color dependency is due to the fact that the red, green and blue primary colors displayed by the pixels may change in different proportions with the viewing angle of the observer. Therefore, the color obtained as a mixture of the red, green and blue primary colors changes according to the viewing angle of the observer.
In order to solve this problem, a new mode of LCD panel has been developed. In the new mode LCD panel, each pixel electrode is partitioned into a main pixel electrode and a subpixel electrode so that the pixel electrode can simultaneously represent different luminance levels. The new mode LCD panel may include different switching devices connected to the main pixel electrode and the subpxiel electrode, so that different pixel voltages can be simultaneously applied to the main pixel electrode and the subpixel electrode. Alternatively, the new mode LCD panel may have an additional capacitor between a switching device and the subpixel electrode while no capacitor is provided between the switching device and the main pixel electrode. It is desirable to find ways to more effectively apply different pixel voltages to the main pixel electrode and the subpixel electrode in new mode LCD panels.